Fuel feeding to resonance type jet propulsion engines



R. E. HOULE Oct. 9, 1956 FUEL FEEDING TO RESONANCE TYPE JET PROPULSIONENGINES Filed April 2, 1952 4 Sheets-Sheet 1 m v, mw M m R a m A R N Ewmw MW m E M% mm mm w q f Hi In Y m II I mm 1/ I I, 1 n I iv m V. f \l EI 4 mm Q N R. E. HOULE Get 1956 FUEL FEEDING TO RESONANCE TYPE JETPROPULSION ENGINES Filed April 2, 1952 4 Sheets-Sheet 2 INVENTOR.ROBERI' E. HOULE AITORNEY cit. 9, 3956 R. E. HOULE 2,765,618

FUEL FEEDING TO RESONANCE TYPE JET PROPULSION ENGINES Filed April 2,1952 4 Sheets-Sheet 3 JNVENTOR. ROERTE. H0045 R. E. HOULE FUEL FEEDINGTO RESONANCE TYPE JET PROPULSION ENGINES Filed April 2, 1952 4Sheets-Sheet 4 N0 COMBUSTION N0 DE T ONA T/ON INVENTOR. RQBERT' E. HOULERICH MQQWWMVQ 0 LEAN ATTORNEY FUEL Unite FUEL FEEDING TO RESONANCE TYPEJET PROPULSION ENGINES The present invention relates to jet propulsionengines, and is particularly directed to improved apparatus for feedingfuel to resonance type jet propulsion engines. This application is acontinuation-in-part of my co-pending applications Serial No. 32,064,filed June 10, 1948, now abandoned; Serial No. 129,110, filed November23, 1949; and Serial No. 238,173, filed July 23, 1951.

As set forth in the last mentioned of the above copending applications,the utilizable power output of existing jet propulsion engines, whetherram jets, turbine jets, internal reaction rocket motors or resonancejets, is never more than a relatively small fraction, often not morethan 20 to 25%, of the theoretically calculated output thereof. Thecalculated theoretical output is determined as the difference betweenthe energy that may be released in the complete molecular reaction ofthe combustible mixture involved and the sum of the energy necessary toinitiate the molecular reaction and the heat of formation of thecombustion and its products.

The great disparity heretofore existing between the energy actuallyobtained from a given quantity of the combustible mixture and the energythat one would expect to be made available by a complete molecularreaction has been explained as resulting from the fact that, what hasbeen assumed to be a homogeneous combustion process, is in reality, inthe chemical gas phase, only an incomplete reaction. During thisincomplete reaction, the fuel molecules have random wave lengths andonly a very small number of the fuel molecules in the combustiblemixture are sufficiently excited and ionized to cause criticalconcentrations of dissociated atoms and radicles forming newcombinations and leading to heterogeneous reactions in the gas phasewhich are of a superior type or order of reaction and effect theliberation of molecular energy. Further, when only a relatively few ofthe fuel molecules are sufficiently excited, the slower movingmolecules, that is, those of greater wave lengths, havea tendency todamp out the effects of collisions between the few sufiiciently excitedmolecules, and reactions of the superior type or order, effectingrelease of molecular energy, are thereby discouraged.

In order to provide an engine of the resonance jet type wherein acombustion reaction in the fuel gases of a superior order or type isobtained so that the actual power output of the engine closelyapproaches the theoretically calculated power output thereof, I haveproposed, in my co-pending applications, identified above, thatcombustion of the fuel mixture be obtained by violent detonation, asdistinguished from the relatively slow and incomplete combustionoccurring in existing engines, with the violent detonation being causedby the production of shock waves within the jet tube of frequency andmagnitude sufficient to effect dissociation of the fuel moleculestoprovide dissociated atoms and -radicles in a reaction releasingmolecular energy.

The excitation or activation of the fuel molecules in a combustiblemixture may be achieved by a combination States atent of pressure andtemperature. It is known that, for a given combustible mixture, thereexist certain critical conditions which, upon their occurrence, change arelaand, if a uniformly relatively low temperature is maintained whilethe pressure is varied, the initiation of detonations will coincide withthe occurrence of high pressure peaks.

The mode of operation of any resonance jet engine is well understoodinsofar as it involves the transmission of a series of pulses orexplosions along a tube, with the direct and reflected pulses meetingand coalescing to divide the tube into a series of vibrating parts,called ventral segments, each separated from the next adjacent segmentsby points of apparent rest, called nodes. Each nodal point is an area inwhich variable pressures are generated, and if the variable pressuresreach sufficiently high values, at or near the peaks thereof, they mayproduce violent detonation of the combustible mixture introduced to thejet tube. In my co-pending applications, identified above, I haveproposed that the production within the jet tube of shock waves offrequency and magnitude effecting violent detonation of the fuelmolecules to provide dissociated atoms and radicals in a reactionreleasing molecular energy may be obtained by rhythmically phasing theinflow of a combustible mixture to the combustion chamber at a frequencywhich is harmonically related to both the acoustic resonant frequency,or fundamental frequency, of the jet tube at operating conditions andthe natural frequency of the fuel molecules during detonation, and in amanner to produce shock Waves in the tube of amplitudes greater thanapproximately decibels.

I have now found that, while the above mentioned conditions, set forthin detail in my co-pending applications, produce the desired violentdetonation of the combustible mixture so that optimum etliciency isattained in utilizing the latent energy of the fuel moleculesparticipating in the detonation, the attainment of maximum power outputand fuel economy for a given resonance type jet engine requires stillfurther control of the fuel admitted thereto. Thus, I have found itdesirable, not only to control the overall proportions of fuel and aircontained in the combustible mixture to obtain a mixture that issusceptible to being detonated at the peak pressures generated by theshock waves, but also to control the flow of the fuel component of thecombustible mixture so that such flow is pulsating and the rate of fuelflow is related to the amplitude of the peak pressures occurring in thejet tube capable of producing detonation.

Accordingly, an object of the present invention is to provide apparatusfor feeding fuel to a resonant jet engine of the described character,wherein the flow of fuel-is pulsatingly synchronized with the pressurevariations within the combustion chamber or jet tube so that the fuelcomponent of the combustible mixture flows at a periodically varyingrate effective to concentrate the fuel flow into intermittent burstscorresponding in quantity to the amplitude of the peak pressures in thecombustion chamber.

Another object is to provide apparatus for feeding fuel to a resonantjet engine of the described character,

wherein the pressure causing flow of the fuel component of thecombustible mixture is varied in synchronism with the varying pressurein the combustion chamber or jet tube so that the rate of flow of fuelinto the com- 3 bustion chamber is correspondingly varied in accordancewith the pressure variations in the combustion chamber.

A further object of the present invention is to provide means forfeeding a pulsating flow of fuel to the combustion chamber of aresonance jet engine of the described character, wherein the pulsationsof the fuel are controlled in relation to the variable pressure in thecombustion chamber and including provision for adjusting the influenceof the variable pressure on the fuel flow.

A still further object of the present invention is to provide anarrangement for feeding fuel to a resonance jet engine of the describedcharacter wherein the fuel component of the combustible mixture iscaused to fiow in a pulsating manner related to the variable pressureproduced in the combustion chamber or jet tube, and including means forcontrolling the influence of the variable pressure in the combustionchamber upon the characteristics of the pulsating fuel flow and meansfor controlling the rate of fuel flow.

A still further object of the present invention is to provide anarrangement for feeding fuel to a resonance jet engine of the describedcharacter as set forth in the preceding paragraph, and wherein the meansfor controlling the rate of fuel flow and the means for controlling theinfluence of the variable pressure upon the characteristics of thepulsating fuel flow are coordinated so that as the rate of fuel fiow isincreased the effectiveness of the variable pressure in the combustionchamber upon the fuel flow is reduced.

The above and other objects, features and advantages of the inventionwill be apparent in the following detailed description of illustrativeembodiments thereof which is to be read in connection with theaccompanying drawings, wherein:

Fig. 1 is an axial sectional view of a resonance jet engine having afuel feeding assembly associated therewith which is constructed andarranged in accordance with the present invention;

Fig. 2 is an axial sectional view of another form of resonance jetengine having a fuel feeding assembly associated therewith which isconstructed and arranged in accordance with another embodiment of thepresent invention;

Fig. 3 is an axial sectional view of still another form of resonance jetengine having the fuel feeding assembly of Fig. 2 associated therewith;

Fig. 4 is a detail view of a throttle arrangement form ing a part of thefuel feeding assembly of Fig. '1;

Fig. 5 is a graphic representation illustrating the fuel flow conditionsfor detonation in resonant jet engines of the described character;

Fig. 6 is a detail sectional view of a part of the fuel feeding assemblyin Fig. 2 or Fig. 3; and

Fig. 7 is a graphic representation illustrating the relationship betweenthe rate of fuel flow and the pressure in the combustion chamber for afuel feeding arrangement embodying the present invention.

Referring to Fig. 1 of the drawing, a resonance jet engine is thereshown of the kind that is fully described in my above-identifiedco-pending applications. This resonance jet engine includes a combustionchamber 25 having a jet tube 26a extending from the rear end thereof anda spark plug or igniter 65 extending into the combustion chamber forstarting the engine. As described in my co-pending application, fuelfrom the tank 79 passes through the feed line 63, having a control valve64interposed therein, into a fuel nozzle 82. N02- zle 82 extends axiallythrough the center of the air inlet head 88 and connects to the staticfuel discharge head 84 which discharges the fuel radially into anintermediate air-fuel inlet section 85 where it is mixed with airentering through the apertures 87 of the air inlet head 88,

From the section 85, the air-fuel mixture enters into the central cavity97 of the mixer head 86 and discharges from the latter through thepassages 94. The secured together elements 88, 85 and 86 are disposedwithin the streamlined cowl 81 and air enters the latter at the openfront end 80 thereof. Such entering air flows into the aforementionedpassages 87 of the air inlet head 88 and also through the annular space81a defined between the cowl 81 and the head 88 for entrance into thepassages 95 of the mixer head 94.

An air line 113 extends from the top of fuel tank 79 to the cowl 81 tocommunicate the air pressure in the latter to the surface of the fueland has a control valve 114 interposed therein. Thus, when the airpressure in the cowl 81 is relatively high, as hereienafter indicated,

the flow of fuel in line 63 will be encouraged, and when the airpressure in the cowl is lower than atmospheric pressure, as hereinafterindicated, the flow of fuel through line 63 will be halted. The radialtongues 105 and 108 of the valve plates secured to the rear face ofmixer head 86 serve to control the dew of fluid out of the passages 95and 94, respectively, of the mixer head. When an explosion in thecombustion chamber 25 increases the pressure in the latter, the tongues105 and 108 are seated against the open ends of the respective passagesto stop the flow of fluid through the latter. When the pressure in thecombustion chamber is decreased by movement of the gases therein towardthe exhaust end of the jet tube 26a, the pressure in front of thetongues 105 and 1025 becomes greater than the pressure behind the latterand the tongues are induced to move away from the ends of the respectivepassages to uncover the latter and permit flow therethrough. When airflows through the passages 95 of the mixer head, the pressure in line113 is decreased to create a suction therein, while cessation of theflow through passages 95 results in an increase in the pressure in line113. The pressure changes in the annular space within the cowl 81 andhence in the line 113 which opens radially into the cowl are produced asfollows:

When the gases in chamber 25 are moving toward the exhaust end of thejet tube 26a, the area in the combustion chamber immediately in back ofthe tongues 105 and 108 is evacuated and attains a relatively lowpressure less than that existing in front of the tongues to causeopening of the latter. When the tongues 105 and 108 open, the air andfuel mixture flows into the combustion chamber through the passages 94and 95, from an area of relatively high pressure to an area ofrelatively low pressure. Thus, when the tongues are opened, a flow ofair is induced through the cowl 81. Since the line 113 is a static head,in effect, the pressure in line 113 will drop as the velocity of fiowthrough the cowl increases. When tongues HES and 108 are again closed bythe occurrence of the next detonation or peak pressure in the combustionchamber, the inertia of the air flow through the cowl 81 causes the airto continue to enter the cowl and to ram or build-up against the closedtongues for increasing the pressure within the cowl and sensed by theline 113.

It is to be understood that the variations in pressure within the cowl81 are of the same frequency as the pressure peaks occurring within thecombustion chamber and also that the amplitude or magnitude of thepressure changes occurring within the cowl 81, and hence sensed by theline 113, is proportional to the amplitude of the pressure peaks in thecombustion chamber. That is, when thepressure peaks within thecombustion chamber increase, the speed of the air flow through the cowl81, with the tongues and 108 open, is correspondingly increased toreduce the low pressure in'the cowl,

and, when the tongues are closed, the inertia of the in-' chamber 25 areincreased, the peak pressures acting on the surface of the fuel in tank79 are similarly increased :above manner has various advantages. :mitsthe accurate control of the proportions of the fuelto increase thequantity of fuel contained in each burst or pulse from the nozzle 82.Since the amount of fuel that can be detonated is greater for relativelyhigh peak pressures in the combustion chamber than for relatively lowpeak pressures in the combustion chamber, the above described actionwill always provide the greatest quantity of fuel in the combustionchamber that can be detonated by the peak pressures then occurring inthe combustion chamber. Further, by properly selecting the lengths ofthe lines 113 and 63, and hence the time lag between the sensing of apressure change at the end of line 113 and the corresponding change inthe rate of fuel flow emitted from the nozzle 82, the phasing of thefuel pulses can be adjusted so that the fuel pulses occur when thetongues 105 and 108 are open.

The feeding of fuel to a resonance jet engine in the First, it per- .airmixture for each charge so that the necessary fuel- :air mixture forviolent detonation of each charge may be conveniently obtained. That is,the period and quantity of fuel flow into the mixing chamber is relatedto the character of the varying pressure in the combustion chamber.Further, greater fuel economy is obtained in that fuel flows from thetank 79 only in intermittent pulses which are related in character andin total quantity per pulse to the varying pressure in the combustionchamber.

Referring now to Fig. 2, another arrangement is shown for obtainingintermittent or pulsing fuel flow in association with a resonance jetengine of the type disclosed in my co-pending applications Serial No.129,110, filed November 23, 1949; and Serial No. 238,173, filed July 23,1951.

The resonance jet engine of Fig. 2 includes a combustion chamber 25 andjet tube 26a joined together and disposed within a jacket 21. Theforward end of combustion chamber 25 is closed by a back plate 28athrough which a cluster of air inlets, generally indicated by referencenumeral 67a, extend. Each air inlet 67a includes a pipe 71 passingthrough plate 28a and having a flared forward end 72 to receive airentering at the front end of the jacket 21 and flowing through thelatter in the direction of the arrows on Fig. 2. The rear end of eachpipe 71 is cut on an angle, asat 73, and a resilient fin or vibratingmembrane 78 is supported to overlie the rear inclined end of the pipe.

Fuel is admitted to the combustion chamber 25 through an axiallyextending pipe 63a which projects through the center of back plate 28aand carries a nozzle 62 at its end within the combustion chamber. Inaccordance with the present invention, the fuel flowing through the pipe63a is made to pulsate in accordance with pressure variations within thecombustion chamber. Accordingly, a section of fuel supply line 63b,extending from the tank 79a and having a valve 64 interposed therein, isconnected to the inlet port of a fuel pump assembly, generally indicatedby the numeral 125 and shown in detail in Fig. 6, while another sectionof the fuel supply line 63 extends from the outlet port of the fuel pumpassembly to the fuel supply pipe 63a.,

As seen in Fig. 6, the fuel pump assembly 125 lncludes a cylinder 126having a piston 127 reciprocable there n. A check valve 128 ispositioned at the inlet port of cylinder 126 to permit flow through saidinlet only in the direction from tank 79a toward the cylinder, whileanother check valve 129 is located at the outlet port of cylinder 129 topermit flow therethrough only in the direction from said cylinder towardthe pipe 63a. An actuating cylinder 130, having a piston 131 slidableaxially therein, is arranged in axial alignment with cylinder 126 and aconnecting rod 132 connects the pistons 127 and 13.1. A pipe or conduit133 opens into cylinder 130 at the side of piston 131 remote fromcylinder 126 and connects to the combustion chamber 25 of the associatedresonance jet engine. When the pressure in the comm bustion chambervaries, the pipe 133 communicates such pressure changes to the cylinderfor action against the piston 131. Thus, when an explosion or detonationoccurs in the combustion chamber, the resultant high pressure causes thepiston 131 to move to the left, as viewed in Fig. 6, and the connectingrod 132 serves to similarly move the piston 127 of the fuel pumpingassembly 125. When a low pressure or suction is created in thecombustion chamber, by the movement of the products of combustion in thedirection of the arrows on Fig. 2 toward the open end of the jet tube,that suction acts on the piston 131, through the pipe or conduit 133, tomove piston 131 toward the right, as viewed in Fig. 6, and the piston127 similarly moves in the same direction. During movement of piston 127to the right, as above, that is, the suction stroke, valve 128 is openedand valve 129 is closed to draw a charge of fuel from tank 79a throughline 63b and valve 64 into cylinder 126. When piston 127 subsequentlymoves to the left,-

as viewed in Fig. 6, that is, during the pumping stroke, valve 128 isclosed and valve 129 is opened, so that the fuel charge is pumpedthrough fuel line 63 and pipe 63a for discharge through the nozzle 62into combustion chamber 25. It is apparent that, during a pumping strokeof piston 127, the speed of movement of the latter will vary inaccordance with the increasing and then decreasing pressure incombustion chamber 25 so that the piston 127 travels at a variable speedwhich is proportional to varying pressure in the combustion chamber.Further it is apparent that the rate of discharge of the fuel throughnozzle 62 will vary in accordance with the speed of movement of piston127 so that the rate of fuel discharge into the combustion chambervaries in accord- ,ance with the pressure developed in the latter.Referring to Fig. 7, wherein the solid line represents the pressure inthe combustion chamber during successive operating cycles and the brokenlines represent the rate of fuel flow during each successive cycle withfuel feeding device constructed in accordance with Figs. 2 and 6, itwill be noted that fuel is discharged into the combustion cham-' ber foreach of the periods of pressure p and that the fuel flow is interruptedfor a period corresponding to the time that a suction s is developed inthe combustion chamber. Further, it will be noted that the maximum rateof fuel flow 1 is proportional to the amplitude of the peak pressure.Since the pressure required to detonate a lean fuel-air mixture is lessthan the pressure required to detonate a rich mixture, the abovedescribed coordination between the rate of fuel flow and the pressure inthe combustion chamber ensures that the mixture supplied to thecombustion chamber has a richness which is proportional to the peakpressures developed in the combustion changer so that violent detonationof substantially all the fuel molecules may be achieved. Thus, theimproved power output or efficiency associated with violent detonationof the fuel, as compared with relatively slow combustion thereof, isachieved with respect to all of the fuel molecules, so that the overallefiiciency is enhanced. Further, since the greater power output isachieved with respect to all of the fuel molecules, a given power outputmay be realized with a smaller fuel consumption.

It should also be noted that the relationship between the-rate of fuelflow and the pressure in the combustion chamber illustrated in Fig. 7,permits the operation of the associated resonance jet engine in a mannerto obtain peak power output from the latter. Since the high rate asubstantially constant rate of discharge of fuel into the combustionchamber during a pressure phase, the rate of discharge cannot be greaterthan that providing a detonatable mixture for the conditions of lessthan peak pressure at the beginning and end of the pressure phase. Thus,at the peak pressure, the fuel mixture is leaner than required in orderthat it may be sutficiently lean during the periods when less than peakpressure is present. Accordingly, it is apparent that a substantiallyconstant rate of fuel flow during the pressure phase requires thedischarge of less than the maximum volume of fuel that may be detonatedwith the peak pressure involved, while varying the rate of fuel fiow inaccordance with the present invention permits the detonation of themaximum volume of fuel with a corresponding maximum power output.

Since the pressure developed in the combustion chamber controls the rateof fuel discharge from the nozzle 62, that rate of fuel flow willprogressively increase With each successive pressure phase. That is,each discharge of fuel at the varied rate necessary for violentdetonation provides a pressure peak greater than the highest pressure inthe preceding pressure phase so that the fuel fiow progressivelyincreases to increase the power output up to an optimum value. However,when the rate of fuel flow exceeds that providing the optimum poweroutput, further increases in fuel flow tend to discourage violentdetonation with consequent loss in power output and efiiciency.

In order to prevent increase of the rate of fuel flow beyond that valueproviding optimum power output, the assembly illustrated in Fig. 6includes structure for limiting the length of stroke of piston 127. Thisstructure includes a collar 134 fixed on the connecting rod 132 andengageable against an adjustable stop 135. Stop 135 has a Worm shaft 136extending threadably therethrough, with the shaft 136 being rotatablysupported in suitable brackets 137 and having an actuating crank 138 onone end thereof. Rotation of stop 135 is prevented by suitablestructure, for example, the illustrated rod 139 on which the stop isslidable. Thus, rotation of screw shaft 136 displaces the stop 135 tovary the permitted stroke of collar 134 and hence of piston 127. Bycontrolling the stroke of piston 127, the volume of fuel admitted to thecombustion chamber may be adjusted to the volume providing a stabilizedcondition of optimum power output.

While the tendency of the arrangement in Fig. 6 is to progressivelyenrich the fuel-air mixture, the first described embcdiment of Fig. 1tends to progressively lean out the combustible mixture as the poweroutput increases. That is, as the speed of the air entering passages 95increases during the intervals between successive pressure phases in thecombustion chamber, the suction in line 113 similarly increases to morecompletely interrupt the fuel fiow through line 63. Thus, merely openingvalve 64 in the fuel line to supply greater quantities of fuel for theincreased power output will not prevent a starving tendency resultingfrom the action of the suction in line 113. For that reason, a valve 114is provided in the suction line 113 and, as the fuel supply valve 64 isprogressively opened, the suction controlling valve 114 is progressivelyclosed.

In Fig. 4, I have illustrated a simple device for simultaneouslyeffecting manipulation of the valves 64 and 114. This device 14)includes a disc 141 having an actuating handle 142 extending therefromand mounted for rotation on the pivot 143. The valve member of valve 114has an arm 144 extending therefrom which is pivotally connected to oneend of a link 145 having its other end pivotally connected, as at 146,to a suitable location on the disc 141. The valve member of valve 64similarly has an arm 147 extending therefrom for connection to a link148 which is attached to disc 141, as at 149. The disc 141 is formedwith series of openings for attachment of the links and 148 thereto sothat the differential movements of the valves 64 and 114 may be adjustedas desired. As illustrated, the disc 141 may be provided with a pointer150 which cooperates with a suitably calibrated scale 151 to indicatethe conditions of valves 64 and 114. With the device of Fig. 4, theinfluence of the suction in line 113 on the fuel flow may be reduced asthe suction increases with increasing power output so that the mixturewill not be leaned-out beyond the value at which violent detonation maybe achieved.

In order to further control the effectiveness of the suction or lowpressure induced in line 113 in influencing the flow of fuel throughline 63 in the embodiment of Fig. 1, provision is made for varying thevolume of air disposed above the fuel level in tank 79. Variation of thevolume of air disposed above the fuel in tank 79 is obtained in theillustrated embodiment by providing the tank with a vertically movabletop wall 79a through which the line 113 projects. Adjustment of theposition of top wall 79a may be effected by any suitable mechanism, forexample, the simple arrangement shown in Fig. l, which includes a leverarm 152 pivoted adjacent its center on a suitable support 153 andconnected at one end to the tank Wall 79a by a link 154. A handle 155may be provided at the other end of lever 152, and a perforated quadrant156 may be disposed adjacent to the lever to receive a pin carried bythe latter for retaining the lever and tank top wall in adjustedposition.

When starting the engine, top wall 79a of the tank is adjusted toprovide a small space above the surface of the fuel therein so that thevariations in pressure in line 113 will be immediately felt within thetank to influence the fuel flow through line 63. As the engineapproaches its normal operating condition, and the variations in thepressure in line 113 become more pronounced, the space above the fuelmay be enlarged so that a reduced pressure in line 113 is only partiallyfelt in the tank and the starving-out heretofore referred to may becontrolled or eliminated.

Referring to Fig. 5, the relationship between fuel consumption and thepressure developed in the combustion chamber is there illustrated. Thelines a and b representing the pressure slope and the constantdetonation slope cross or intersect at the point 0, which pointcorresponds to the production of the peak pressure, as indicated by thedotted line. With the arrangement of Fig. 1, the engine is started inthe extreme rich condition, and the mixture is leaned out in thedirection of arrow 152 until detonation is achieved. The suction in line113 then automatically serves to further lean-out the mixture until thepeak pressure is obtained and this condition is then stabilized with thecontrol arrangement of Fig. 4. With the fuel feeding arrangement ofFigs. 2 and 6, the resonance jet engine is started in the extreme leancondition and the mixture is enriched in the direction of arrow 153 ofFig. 5 until it is suflicient to sustain combustion. The pump 125,operated by the varying pressure in the combustion chamber, then servesto further enrich the mixture until the peak pressure of violentdetonation is achieved, and that condition is stabilized by theadjustable stop 135 for limiting the stroke of the piston 127.

Referring now to Fig. 3, a fuel feeding arrangement of the kind shown inFigs. 2 and 6 is there shown associated with a resonance jet engine ofthe type described in my co-pending application Serial No. 238,173,filed July 23, 1951. This resonance jet engine includes an outer tube orjacket 21 having a concentric combustion chamber 25 thereincommunicating with a rearwardly extending jet tube 26 through anintermediate stepdown section 27. The forward end of the combustionchamber is closed by a rearwardly concave back plate 28. A forwardlyopening, bell-shaped member 115 is supported in jacket 21 ahead of thecombustion chamber by structure which includes horizontal arms 118 and avertical streamlined spar 117 and is intended to receive air entering atthe front end of the jacket 21 and flowing through the latter in thedirection of the arrows on Fig. 3. A fuel supply line 119 extends intospar 117 and the latter is formed with discharge openings 120 at thetrailing edge thereof to discharge fuel into the member 115. A series offlexible pipes 122 extend from openings in the rear portion of member115 to carry the fuel-air mixture to associated injector assemblies 123which are constructed and arranged to discharge a phased fuel-airmixture into the combustion chamber through related openings in the backplate 28.

As set forth in my above identified co-pending application, theinjectors 123 are operated by the explosions in the combustion chamberto propel the fuel-air mixture into the latter. Since the injectors 123form no part of the present invention, the construction thereof will notbe described in detail. However, it may be noted, generally, that eachof the injectors 123 includes an impeller which is arranged to berotatably driven by the back pressures accompanying detonations in thecombustion chamber, and the rotated impeller in turn pumps the fuel airmixture into the combustion chamber. As seen in Fig. 3, the fuel line119 is connected to the outlet port of the pumping cylinder assembly125a which is the same as the assembly 125 in the device of Figs. 2 and6. The piston of the assembly 125a is operated by a connecting rod 132aextending from the piston in an actuating cylinder 130a while the pistonin the latter moves in response to the pressure variations in combustionchamber 25 by reason of the conduit 133a communicating cylinder 130awith the combustion chamber. Thus, the rate of fuel flow through line119 and the quantity of fuel included in each pulse will be controlledby the pressure peaks in the combustion chamber.

The engine of Fig. 3, as in the case of the engine in Fig. 2, is startedwith an extremely lean mixture, and the fuel feeding arrangement servesto increase the richness of the mixture as the power increases.Accordingly, means similar to the stop 135 of Fig. 6 are associated withthe connecting rod 132a to limit the stroke of the fuel pumping pistonso that the mixture may be stabilized at the condition producing violentdetonation of the fuel.

From the foregoing it is apparent that the present invention providesmeans for feeding a pulsing flow of fuel to resonance jet engines of thedescribed character wherein the rate of fuel flow is related to thevarying pressure produced in the combustion chamber so that the maximumrate of fuel flow coincides with the occurrence of the peak pressure tothereby provide a mixture which is susceptible to violent detonation atall stages of the pressure phase. Further, it is apparent that deviceshave been provided for adjusting the influence of the combustion chamberpressure upon the rate of fuel flow so that the latter may be maintainedin a stabilized pattern producing violent detonation of the fuel foreffecting a reaction forming dissociated atoms and radicles andreleasing molecular energy.

While I have described and illustrated several specific embodiments ofmy invention, it should be noted that the invention is not limited tothese precise embodiments, and that changes and modifications may bemade therein without departing from the scope of the invention asdefined in the appended claims.

What I claim is:

1. In a resonance jet engine; the combination of an elongated tubedefining a combustion chamber at one end, means defining a mixingchamber, means defining passages communicating said mixing chamber withsaid combustion chamber, means for supplying fuel to said mixingchamber, means for supplying air to said mixing chamber, and valve meansin said passages responsive to the pressures at said one end of the tubeto open and close at a frequency which is harmonically related to thenatural frequency of the fuel molecules and to the fundamental frequencyof said tube so that the mixture of air and fuel fed through saidpassages produces a standing shock wave in said tube, pressureresponsive meafi's con nected to control said fuel supply means toprovide a pulsing flow of fuel having periods of flow at thesamefrequency as the occurrence of elevated pressures in said combustionchamber and quantities proportional to the.

amplitude of the elevated pressures.

2. In a resonance jet engine; the combination accord.

ing a cylinder having a piston reciprocatable thereirr,

means connecting the last mentioned piston with said pumping piston anda conduit communicating said combustion chamber with said cylinder sothat the piston in the latter is displaced in one direction in responseto an elevated pressure in said chamber and in the opposite direction inresponse to a reduced pressure in said chamber, the speed ofdisplacement of said actuating piston and of said pumping piston beingproportional to the rate of increase of the elevated pres-sures in saidchamber so that the rate of fuel flow through said fuel feeding line inresponse to the occurrence of said elevated pressures varies inaccordance with the rate of increase of said elevated pressures.

4. In a resonance jet engine; the combination according to claim 3,including means for varying the influence of the elevated pressures insaid chamber upon the quantity of fuel discharged by said pumping meansduring eacln stroke of the piston thereof.

5. In a resonance jet engine; the combination accord ing to claim 4,wherein the last mentioned means includes an adjustable stop and amember movable with said pumping piston and engageable against stop tolimit the length of the stroke of said pumping piston.

6. In a resonance jet engine; the combination according to claim 1,wherein said air supplying means operates to provide a high speed airflow through said mixing chamber during periods of reduced pressure insaid combustion chamber and a relatively low speed air flow through saidmixing chamber during periods of elevatedpressure in said combustionchamber, and wherein said means providing a pulsing flow of fueloperates in response to the pressure in the pulsing flow to provide arate of fuel flow varying inversely with said pressure in the pulsingair flow.

7. In a resonance jet engine; the combination of an in said chamber anda relatively low speed air flow during periods of elevated pressure insaid chamber at a fre-,

quency which is harmonically related to the naturally frequency of thefuel molecules and to the fundamental frequency of said tube to producea standing shock wave in said tube, and means providing a pulsing flowof fuel including an air line opening at one end at the air flow tosense the pressure in the latter and communicating with said tank abovethe fuel in the latter so that the pressure acting on the fuel in thetank varies in accordance with the pressure in the air flow toalternately retard and advance the gravity induced flow of fuel throughsaid fuel feeding line at the same frequency as the occurrence ofelevated pressures in said combustion chamber.

8. In a resonance jet engine; the combination accord,-

ing-to claim7, including means for adjusting'the influence of pressurevariations in the air flowupon the rate of fuel flow through said fuelfeeding line.

9; In a resonance-jet engine; the'combination acccordto claim 8, whereinthe last mentioned-means includes a first valve interposed in saidairline for restricting the latter.

10. In a resonance jet engine; the combination according to claim 9,wherein said fuel supplying means includes a second valve interposed insaid fuel feeding line to vary the rate of fuel fiow through the latter,and including means operatively connecting said first and second valvesfor progressively closingsaid first valve as said second valve isopened.

11. In combination; a resonance jet engine having a combustion chamber,a mixing chamber communicating with said combustion chamber, valve meansbetween said mixing and combustion chambers operating at'the frequencyof pressure variation in the combustion chamber to open and close thecommunication between said chambers, means for supplying air to saidmixing chamber, means supplying a pulsing flow of air to said combustionchamber at a frequency operative to acoustically produce intermittentelevated pressures in said combustion chamber, and means for supplying apulsing flow of fuel to said mixing chamber at a rate of flow whichvaries at the-same frequency as the acoustically produced intermittentelevated pressures and is volumetrically proportional to the amplitudesof said elevated pressures.

12. The combination according to claim 11; wherein said means supplyingair to the combustion chamber operates to provide a rate of air flowvarying substantially inversely with the pressure in said combustionchamber, and wherein said fuel supplying means includes a devicesensitive to the pressure in the air flow to said combustion chamber.

13. In combination; a resonance jet engine having a combustion chamber,means supplying a pulsing flow of air to said combustion chamber at afrequency operative to acoustically produce intermittent elevatedpressures in said chamber, with the rate of air flow varyingsubstantially inversely with the pressure in said combustion chamber,and means for supplying a pulsing flow of fuel to said chamber at avarying rate of flow having its maximum coinciding with the occurrenceof maximum pressure in said chamber, said fuel supplying means includinga tank for containing a supply of fuel and a fuel feeding line extendingfrom saidtank to gravitationally conduct fuel to said engine, andadevice sensitive to the pressure in the air flow including an air linedisposed so that the pressure therein varies in accordance with thepressure in the air flow and connected to the top of said tank so thatthe variations of pressure in the air "flow are communicated to thesurface of the fuel supply to influence the rate of fuel flow throughsaid fuel feeding line.

14. The combination according to claim 13; including first means foradjustably restricting said air line to vary the influence of thepressure in the air flow upon the rate of fuel flow through said fuelfeeding line.

15. The combination according to claim 14; including second means foradjustably restricting said fuel feeding line to vary the rate of fuelflow through said fuel feeding line, and means operatively connectingsaid first and second restricting means so that, as said secondrestricting means is adjusted in the direction for increasing fuel flowthrough the fuel feeding line, said first restricting means issimultaneously adjusted to increase the restriction of said air line.

16. The combination according to. claim 11; wherein said fuel supplyingmeans includes a fuel feeding line, pumping means interposed in saidfuel feeding line for elfecting'the flow of fuel through the latter, andpump actuating means responsive to the pressure in said combustionchamber to operate said pumping means so that the latter produces flowthrough said fuel feeding line in response to the occurrence of elevatedpressures in said chamber and at a rate varying in accordance with suchelevated pressures.

17. The combination according to claim 16; wherein said pump actuatingmeans includes a cylinder having an actuating piston therein, a lineopening at its opposite ends into one end of said cylinder and into saidcombustion chamber so that the varying pre ssures in the latter effectreciprocation of said piston, and means operatively connecting saidpiston to said pumping means so that movement of said piston in onedirection draws a fuel charge into said pumping means and movement ofsaid piston in the opposite direction effects discharge of the fuelcharge through the fuel feeding line.

18. The combination according to claim 17; wherein said pump actuatingmeans further includes adjustable means for limiting the stroke of saidpiston so that the quantity of fuel discharged from said pumping meansfor each stroke of said piston in said opposite direction may becontrolled independently of the pressures in said combustion chamber.

19. In a resonance jet engine the combination of an elongated tubedefining a combustion chamber atone end, means for supplying a pulsingflow of air to said chamber and operative to provide a high speed airflow during periods of reduced pressure in said chamber and a relativelylow speed air flow during periods of elevated pressure in said chamber,means for supplying fuel to said chamber including a fuel tank and afuel feeding line extending from said tank for the gravity induced newof fuel therethrough, means providing a pulsing flow of fuel includingan air line opening at one end into the air flow to sense the pressurein'the latter and communicating with said tank above the surface of thefuel in the latter so that the pressure in the space of said tank abovethe fuel varies in accordance with the pressure in the air flow toalternately retard and advance the gravity induced flow of fuel throughsaid fuel feeding line, and means for adjusting the volume of said tankto thereby vary the space above the surface of the fuel so that theinfluence of the pressure in the air flow upon the flow of fuel may becontrolled; 5

References Cited the file of this patent NI s ATEs PATENTS 2,480,540Bodine Aug. 30, 1949 2,505,757 Dunbar etal. May 2, 1950 2,525,782 DunbarOct. 17, 1950 2,546,965 Bodine Apr. 3, 1951 2,581,902 Bodine Ian. 8,1952 2,602,291 Farnell July 8, 1952 2,609,660 Tenney Q. Sept. 9, 1952OTHER REFERENCES Wasted Talent," article in Flight magazine, October 5,1944, page 364 to 370.

